Euglena are unicellular organisms classified into the Kingdom Protista, and the Phylum Euglenophyte. All euglena have chloroplasts and can make their own food by photosynthesis. They are not completely autotrophic though, euglena can also absorb food from their environment; euglena usually live in quiet ponds or puddles.
Euglena move by a flagellum (plural ‚ flagella), which is a long whip-like structure that acts like a little motor. The flagellum is located on the anterior (front) end, and twirls in such a way as to pull the cell through the water. It is attached at an inward pocket called the reservoir. Color the reservoir grey and the flagellum black.
The Euglena is unique in that it is both heterotrophic (must consume food) and autotrophic (can make its own food). Chloroplasts within the euglena trap sunlight that is used for photosynthesis, and can be seen as several rod like structures throughout the cell. Color the chloroplasts green. Euglena also have an eyespot at the anterior end that detects light, it can be seen near the reservoir. This helps the euglena find bright areas to gather sunlight to make their food. Color the eyespot red.Euglena can also gain nutrients by absorbing them across their cell membrane, hence they become heterotrophic when light is not available, and they cannot photosynthesize.
The euglena has a stiff pellicle outside the cell membrane that helps it keep its shape, though the pellicle is somewhat flexible and some euglena can be observed scrunching up and moving in an inchworm type fashion. Color the pellicle blue.
In the center of the cell is the nucleus, which contains the cell's DNA and controls the cell's activities. The nucleolus can be seen within the nucleus. Color the nucleus purple, and the nucleolus pink.
The interior of the cell contains a jelly-like fluid substance called cytoplasm. Color the cytoplasm light yellow. Toward the posterior of the cell is a star-like structure: the contractile vacuole. This organelle helps the cell remove excess water, and without it the euglena could take in some much water due to osmosis that the cell would explode. Color the contractile vacuole orange.
Answer: 12.5 x 10^6/10000 = 1250 cells.
Explanation:
A serial dilution is the step-by-step reduction of the concentration of a solution. Usually, the dilution factor at each step is constant, resulting in a geometric progression of the concentration, which is logarithmic. <u>Serial dilutions are used to create very dilute solutions by accurately reducing the concentration of a substance.</u>
It is usually carried out in experiments where highly dilute solutions are needed, for example, those involving logarithmic scale concentration curves or those used to determine the density of bacteria. To do this, prepare several test tubes with, for example, 9 ml of dilution liquid and first add 1ml of the undiluted sample to the first tube and then make serial dilutions in the following tubes. The first tube will contain a 1:10 dilution, the second 1:100, the third 1:1000, the fourth 1:10000 and so on.
Use 1 ml of undiluted (stock) solution with a pipette into the first test tube, containing 9 ml of a liquid, which can be for example water, Phosphate-buffered saline (PBS) and mix. This is the 1:10 solution. For the second dilution, take 1 ml of the dilution from the 1:10 tube and add it to the 9 ml of liquid to make the 1:100 tube and mix. The third tube is prepared with 1 ml of the 1:100 solution and 9 ml of liquid and this will be the 1:1000 dilution. The last one is prepared with 1 ml of 1:1000 and 9 ml of liquid and it will be 1:10000 (the fourth dilution).
So, if you start with 12.5 million cells and dilute four times with serial dilutions of 1:10 each, the final concentration will be four times lower:
12.5 x 10^6/10000 = 1250 cells.
Los aminoácidos al unirse por enlace peptídico forman también polímeros más pequeños que las proteínas, que se denominan péptidos. ... La bleomicina es un péptido que se encuentra entre los agentes antitumorales.
